The manual material handling tasks in underground low seam mines present a myriad of ergonomic risk factors which places inordinate demands on miners' neuromuscular system. Material handling and scaling tasks in restricted posture will cause potential loss of stability/balance to increase therefore, lifting task analysis should include information about postural stability/balance. Currently such information does not exist for material handling in a static stooped posture and dynamic (gait) stooped posture while exposed to individual and/or combined ergonomic risk factors commonly found in an underground mine. The proposed study provides the design to collect such information in a series of experiments (41 hours of testing on each worker) with miner workers. For example, all experimental conditions (encompassing risk factors such as, restricted work postures, task type, surface slipperiness, surface unevenness, and environmental lighting and glare) to be evaluated in the proposed study will be rank-ordered for postural instability and/or loss of balance using established objective criteria described in Section D. Also, number of slips/falls experienced during the performance of simulated industrial tasks (described in Section D) will allow us to determine the relationship between measures of postural instability and/or loss of balance and actual incidence of slips/falls in the simulated environment. The results will provide enhancement (by adding new risk factor effects) to our existing statistical model of prediction of postural instability assoicated with work place risk factors encompassing environmental, job-task factors. These findings will provide the framework within which future mining worker- population-based prospective studies can be designed to address the following issues. A) Provide guidelines for mining workplace design to allow appropriate sufficient floor spacing so that workers can increase their base of support, minimizing the potential of postural instability. B) The results can be used as scientific data input about postural instability under various combinations of mine related risk factors as input into the MSHA's training programs where softwares are being developed to include human factors issues.